Epithelial cells are closely packed cells that form the epithelium. They are found throughout the body beneath the skin and cover certain organs.
Epithelial cells line the inner and outer surfaces of the body. They are like a continuous sheet of tissues interlinked by cell junctions. Among the surfaces of these cells, one is attached to a non cellular base membrane, that is like an underlying tissue.
There are different types of epithelial cells that form the epithelium. One of the cells contributing to the epithelium are the squamous epithelial cells. They are large and flat scale-like cells forming a sheet-like layer.
When the epithelium consists of one layer of these cells, it is called simple squamous epithelium, and when it has multiple layers of these cells, it is called stratified squamous epithelium. Let us see in detail about each, and also about their functions.
These cells are made up of a single layer of epithelial cells, and are the point of contact for the epithelial tissue with the base membrane.
They can be located in areas that face rapid diffusion like the lining of the lung alveoli (the respiratory units called air sacks), the endothelium (lining of the blood vessels), capillaries, kidneys, lining of the major body cavities (mesothelium), and other major areas where little activity is happening.
Stratified epithelial cells consist of two or more layers of epithelial cells. They are mostly found in areas where most of the wear and tear of the body takes place, like certain areas that get worn away.
For example esophagus, lining of the mouth, and outer areas of the skin. Though these cells have a flat physical form, many of the layers may not adhere to the flat form.
The cells nearer to the skin (the top surface will be flat, however, the ones that are at the base layer may be more cuboidal or columnar. They are found in the epidermis (layer of the skin) and the esophagus. Another type of stratified epithelium lines the urinary bladder and the urinary tract.
Simple squamous cells are responsible for allowing the exchange of oxygen, nutrients and waste. It is responsible for protection of the organs in the abdominal cavity. They are also responsible for the filtration of blood, and diffusion, that allows passing of oxygen in the blood. It also allow water and other substance to pass from the blood in the urine.
It helps in moving of the immune cells from the small blood vessels in the surrounding tissues. Stratified squamous cells have a vital function of protecting the organs. It protects the underlying tissues form abrasions.
The outer layer of this is made up of a protein called keratin that helps in preventing water loss and helps in retaining moisture. It covers up the dry surface of the skin.
Since the squamous epithelial cell is found in most of the organs and skin, there is a danger of it being damaged. A majority of the types of cancer are related to epithelial cells.
Also, the high levels of squamous epithelial cells in urine indicate contamination, and a proper medical examination is advised to detect the exact issue. Depending on the concentration of the cells, a test can detect if the cell count is high or low.
There are many sensitive issues that are related to squamous epithelial cells, so a proper and timely diagnosis and treatment is a wise step for the balance of these vital body tissues.